1. Field of the Invention
The invention relates to a remote terminal interface to a system bus that is adapted to be used in an aircraft stores item, in which small chip-size and low cost are important.
2. Description of the Related Art
In an aircraft in the MIL-STD 1553 context, there is a governmental specification for the functions to be performed by the bus controller and the interface logical units on the remote terminals. One example of a bus interface satisfying the requirements is the remote terminal interface described in U.S. Pat. Nos. 4,625,307; 4,635,253; 4,695,952; and 4,623,997. This prior work was directed at permanent remote terminals that would remain part of the aircraft. In the particular case of an aircraft store, meaning any of a number of devices that are attached to the aircraft with lugs and meant to be dropped or expended in flight, primary considerations are that the chip be small, use low power and be inexpensive, since it typically will only be used once and then discarded. The chip must, of course, perform the functions required of a remote terminal interface but will probably do so in a simpler manner. It has been the case in the prior art that the cost of the electronics required to construct the interface could by itself cost more than the total price of the stores connected to it. The industry has thus felt the need for a low cost, low power interface.